This is part two of an ongoing series about the overhaul of the Fiske Planetarium. For the other parts of the series, click here.
Museums are places of visual learning. Nearly all contain artifacts, dioramas, paintings, and photographs. Only relatively recently has museum theory shifted towards a hands-on approach to educating. Even so, what we see often still carries the bulk of the experience. This is probably even truer in a planetarium. I can't put a star into your hand or a galaxy in a display case. Instead, we have to choose images and videos which can both captivate and educate.
You might think that, given the hundreds of thousands of available astronomical images, this would be a straightforward task. Surely we can just scoop up a few of those flashy Hubble images we see on the news. Things are rarely so straightforward, of course. The main problem in this case is that most of astronomy is done in parts of the spectrum other than what our eyes can see. Thus, any observations astronomers make must somehow be converted into a picture that we can see.
Take for example, the stunning image of the rings of Saturn pictured above. See all those beautiful colors? They're all fake. This image is based on data taken by measuring how the rings block radio waves. Since radio waves don't have colors in the same way visible light does, the scientists had to make up a color scheme. In this case, the colors correspond to the size of the particles in the ring. Since that's the actual information provided by radio measurements, this is a totally valid picture of the rings. Just not one that you could ever see. Most of those famous Hubble images use false color, too. In most of those pictures, the colors represent different elements and molecules observed in space.
Another challenge when selecting images is trying to preserve a sense of scale. Most objects in space are pretty isolated, making it difficult to get a sense of their size. Compositions which can juxtaposition two different bodies can provide powerful imagery. Consider the image of Titan above. Titan is the second largest moon in the solar system, yet Saturn appears enormous behind it. When you realize that Saturn is hundreds of thousands of kilometers away from the moon, you really get a sense of how large the gas giants are. This image has the added bonus of capturing a portion of the rings. Look how delicate they are! The largest, flattest structure in the solar system, neatly posed between a giant moon and an even larger planet.
Sometimes, though, an image just doesn't cut it. The universe is an active place, but you'd hardly know it based on the images we commonly see. From supermassive black holes to the winds of Mars, nearly everything in space is in motion. The drama of nature in action can't merely be captured in a well-timed still, sometimes a video is a must. Check out this GIF of Jupiter's moon Io on the right. Io is probably the most active place in the solar system, with volcanoes that shoot out into space and cover the entire Jovian system with material. Surely seeing this in motion drives home the message of an active universe.
Of course, with so many jaw-dropping images to choose from, it can often be difficult to stay on topic. I admit that sometimes I select an image just based on how cool it looks, and then try and find a way to shoehorn it into my theme. At least the display will be enjoyable to look at!